Describe physical and chemical changes in
matter.
When you crush chalk it
only changes the physical
appearance.
When you spray
vinegar on chalk,
the formation of
gas bubbles
indicates a new
substance has
formed.
Science Standard 8.5.b: Students
know the idea of atoms explains
the conservation of matter. In
chemical reactions the number of
atoms stays the same no matter
how they are arranged, so their
total mass stays the same.
physical change: any change that alters the
form or appearance of matter but does not
make any substance in the matter into a
different substance.
chemical change: a change in matter that
produces one or more new substances.
law of conservation of matter: matter is not
created or destroyed in any chemical or
physical change.
Physical Change
Changes of State
Changes in Shape or Form
Chemical Change
Example of Chemical Change
Conservation of Matter
 The idea of atoms explains the law of conservation of
matter. For every molecule of methane that burns, two
molecules of oxygen are used. The atoms are
rearranged in the reaction, but they do not disappear.
Propane (C3H8) is a fuel that is often
used in camping stoves. When
propane burns, it reacts with oxygen,
producing carbon
dioxide gas and water vapor. The
data table shows how much carbon
dioxide is produced
when different amounts of propane
burn in oxygen.
Interpreting Data:
Based on the data in the
table, how do you know
that carbon dioxide is not
the only substance formed
in this chemical change?
The mass of carbon dioxide is
less than the sum of the
masses of oxygen and
propane.
Calculating:
Copy the data table and add
a new column on the right. In
the new column, enter how
much water vapor is
produced for each amount of
propane burned.
Students should enter the
"missing" mass of the
products.
Graphing:
Use the data in the table to
make a graph. Plot the mass
of C3H8 reacted on the
horizontal axis, and the
mass of CO2 produced on the
vertical axis.
The graph will produce a
straight line.
Reading Graphs:
Use the graph to predict
how much CO2 would be
produced if 100 grams of
propane burned in oxygen.
300 g
 List three kinds of
physical changes that
could happen to a
plastic spoon.
bend, break, melt…
 Why is boiling water
considered a physical
change?
A new substance
does not form.
 Answer #1-4
 Finish the
worksheet.
HOMEWORK EXTENSION
 Write a detailed SUMMARY of the section and
complete the UNANSWERED QUESTIONS section of
your notes.
 Choose two of the remaining Depth & Complexity
ICONS in your notes and explain how they relate to
this section.